Analysis of Dynamic Characteristics of Suspension Structure of Electric Hoist for Stage

The electric hoist studied in this paper is applied to stage lifting, which has higher requirements for safety. Vibration in the course of lifting up and down needs to be studied to eliminate potential safety hazards. This paper analyzes the dynamic characteristics of the stage-use electric hoist with vibration problems during the lifting process, considering the influence of speed and counterweight on the suspension structure. In order to identify the vibration source, the hoist suspension structure consisting of a string of circular chains is analyzed first, which can be equivalent to countless simple pendulum systems during the lifting process. Then another excitation source generated by the collision between the polygonal sprocket and chain during the rotation of the lifting sprocket is analyzed, proven to be the main cause of structural vibration. Finally, the hoist lifting experiments at different speeds with different weights are carried out, during which the accelerations of the amplitude are measured, consistent with the excitation source generated by the rotation of the sprocket. It is found that the rotation of the sprocket is the main reason for the vibration of the electric hoist, and the vibration is affected by the angle and speed of the sprocket.

I. Introduction

The stage-use electric hoist is mainly used to lift various lamp stand props. In the process of lifting heavy objects, the electric hoist will shake and affect the stability of the hanging objects. The research on the suspension structure mainly includes the following steps, firstly, the shimmy motion state of the stage-use electric hoist suspension structure system is measured, secondly, structural modeling and vibration analysis are carried out. Reference [1] divided the movement mode of the suspension structure into translational movement and rotational movement, and proposed a method to measure the swing angle of the suspension structure’s translation and rotation by using an inclination sensor and a gyroscope, respectively. However, the application of gyroscope to measure the rotation has problems, such as integration error and time accumulation error. Image processing technology can also be used to measure the shimmy vibration of suspended structures [2 , 3] . The camera is used to collect the motion image of the suspension structure, a mark that can be identified is installed on the suspension structure, then use the computer to process the collected images to obtain the movement information of the suspended structure. But the light will greatly affect the accuracy of the measurement.